Grinder for timers



July 2, 1929. c. D. PRICE GRINDER FOR TmERs I Filed Sept. 13, 1926 IN VEN TOR ATTORNEY Patented July 2, 1929.

UNITED STATES CHARLES D. PRICE, OF CLINTON, MISSOURI.

GRINDER FOR rIMnRs.

Application filed September 13, 1926. SerialNo. 135,176.

My invention relates to grinding apparatus and more particularly to grinders for timer commutators.

It is a purpose of my invention to provide a grinding apparatus for commutators and similar deviceswhich will quickly and efficiently grind the contact surfaces of the commutator into a. smooth arcuate form without any great amount of skill being required of the operator of the device.

Other objects and advantages of the invention will appear as the. description of the accompanying drawings proceeds. However, I desire to have it distinctly understood that I do not intend to limit myself to the exact details shown or described, but that I intend to include as part of my invention all such obvious changes and modifications of parts as would occur to a person skilled in this art and as would fall within the scope of the claims.

In the drawings:

Fig. 1 is a perspective view of a portion of a grinder, showing my improved grinding device in position thereon and showing the commutator carrying portion of the timer being moved into engagement therewith.

Fig. 2 is a fragmentary sectional view of the grinder, showing the commutator carrying portion of the timer in position thereon so that the grinding face of the abrasive member will be in engagement with the commutator segments, and

Fig. 3 is a transverse sectional view through the grinding device detached from the grinder.

Referring in detail to the drawings:

7 My improved grinder preferably com-. prises a base member 10 having the standard 11 extending upwardly therefrom and carry ing a housing 12 which may contain any suitable means for rotating a shaft 13. The shaft 13 is preferably provided with a stop flange 14 and with a threaded end portion 15. My improved grinding device comprises a sleevelike member 16 having the end flanges 17 and 18, said sleeve-like member embracing the shaft 13 between the nut 19 having screw threaded engagement with the. threaded end 15 of said shaft and the flange 14. Mounted between the flanges 17 and 18 on the tubular member 16 is asubstantially cylindrical abrasive member 20, a gasket of compressible material being preferably provided between the flange 17 and the abrasive member 20 to prevent damage to the abrasive member when the flange 17 is formed on the member 16. A

disk-like member 22 is provided with a hub 23 lying between the flange 18 and one side wall of the member 20, said hub portion being offset from the relatively wide flange portion 24 of said disk-like member by means of the inclined oflset portion 25 to thus space the relatively wide flange portion 24 the proper distance from the hub 23 so that the same will act as a gauge for aligning the abrasive member 20 with the member that is to be operated on.

The flange portion 24 preferably terminates in a laterally extending lip 26 to avoid any sharp edges on the device that might cut the operator.

In use, the timer having the commutator carrying portion 27 which is usually in the form of a cup-like cover, is engaged with the disk-like member 22 by moving the edge portion 28 thereon into firm engagement with the relatively wide flange portion 24. The parts are so proportioned that the commutator segments 29 carried by the insulating ring 30 are then in proper alignment with the abrading member 20 so that the outer cylindrical face 31 thereof will engage with said commutator segments and grind the same to a true smooth cylindrical surface.

The grinding of the commutator segments in the manner set forth above is very important as timers of the nature shown very frequently become extremely rough on the contact faces thereof, causing the co-operating contact frequently to be thrown to such a position that it does not make contact with all of the commutator segments, thus causing the engine associated therewith to miss fire, especially at high speeds. With my improved apparatus the commutator is trued up so as to operate properly at all speeds and the operation of grinding the same can be carried on by anyone by merely engaging the edge of the member 27 with the flange 24 on the disk-like member 22, the flange acting in a similarmanner to a face plate and serving as a stop to gauge the position of the abrading member relative to the commutator.

What I claim and desire to secure by Letters Patent is: V

1. In a device of the character described, an abrading element, means for mounting said abrading element for rotation including a shaft having a lateral flange and a sleeve provided with a flange and'a disk-like stop member rotating with said abrading element,

said stop member having a central hub porashaft having a lateral flange and a sleeve on the shaft having a flange engaging said shaft flange, a disk-like stop member totating with said abrading element and including a hub portion in abutment with a side face of said abrading element and mounted between said element and said sleeve flange, and a relatively Wide peripheral face plate portion offset from the hub portion to space said face plate portion axially from the plane 20 of said abrading element.

In testimony whereof I aflix my signature.

CHARLES D. PRICE. 

